偶极荷电静电除尘器伏安特性及收尘性能研究

提出一种新型的静电除尘器,即偶极荷电静电除尘器,分析了其收尘机理,主要包括离子风、电场力及电凝并,利用PIV技术对离子风进行了测定,并对其伏安特性及收尘性能进行了实验研究,结果表明:离子风速度约为2m/s左右;偶极荷电静电除尘器的电晕电流及对微细颗粒物的除尘效率均远高于普通的静电除尘器。     

滨海新区局部大气颗粒物中多环芳烃污染特征研究

在滨海新区局部区域汉沽和大港采集了TSP和PM10样品,分析了不同颗粒物中多环芳烃的不同期别污染和分布特征,结果表明,多环芳烃的污染水平存在明显的季节性特征,采暖期多环芳烃和可吸入颗粒物中苯并[a]芘浓度均远远高于非采暖期。多环芳烃在不同期别也有不同的分布特征,非采暖期均是高环类多环芳烃占主导地位,比例超过60%;而在采暖期则是中环类多环芳烃占主导。     

上海市冬季可吸入颗粒物微观形貌和粒度分布

应用高分辨率场发射扫描电镜(FESEM)和图像分析技术研究了上海市区冬季(2005-01)大气可吸入颗粒物的形貌特征以及不同种类颗粒物的数量-粒度和等效体积-粒度分布.结果表明,上海市可吸入颗粒物中,矿物颗粒和烟尘集合体普遍存在,还有较多的未燃尽油滴残留颗粒;矿物颗粒有不规则状矿物颗粒、较圆滑矿物颗粒和规则长条状颗粒,烟尘集合体有链状、蓬松状等形态;矿物颗粒在数量和等效体积上平均分别占75%和64%,烟尘集合体在数量和等效体积上平均分别占25%和36%,矿物颗粒较多说明上海市冬季受扬尘影响较重;上海市区PM₁₀的粒径主要分布在较细的范围内,其数量-粒度分布和体积-粒度分布随时间有明显的变化,白天矿物颗粒、烟尘集合体的数量分布的峰值分别出现在0.1～0.3、0.2～0.3 μm;晚上2种矿物颗粒、烟尘集合体的数量分布的峰值分别出现在0.3～0.5 μm、0.4～0.6 μm,呈现晚上颗粒物粒径较大的倾向.     

Source profiles of particulate organic matters emitted from cereal straw burnings

Cereal straw is one of the most abundant biomass burned in China but its contribution to fine particulates is not adequately understood. In this study, three main kinds of cereal straws were collected from five grain producing areas in China. Fine particulate matters （PMzs） from the cereal straws subjected to control burnings, both under smoldering and flaming status, were sampled by using a custom made dilution chamber and sampling system in the laboratory. Element carbon （EC） and organic carbon （OC） was analyzed. 141 compounds of organic matters were measured by gas chromatography-mass spectrum （GC-MS）. Source profiles of particulate organic matters emitted from cereal straw burnings were obtained. The results indicated that organic matters contribute a large fraction in fine particulate matters. Levoglucosan had the highest contributions with averagely 4.5% in mass of fine particulates and can be considered as the tracer of biomass burnings. Methyloxylated phenols from lignin degradation also had high concentrations in PM2.5, and contained approximately equal amounts of guaiacyl and syringyl compounds. 13-Sitostrol also made up relatively a large fraction of PMz5 compared with the other sterols （0.18%-0.63% of the total fine particle mass）. Normal alkanes, PAHs, fatty acids, as well as normal alkanols had relatively lower concentrations compared with the compounds mentioned above. Carbon preference index （CPI） of normal alkanes and alkanoic acids showed characteristics of biogenic fuel burnings. Burning status significantly influenced the formations of EC and PAHs. The differences between the emission profiles of straw and wood combustions were displayed by the fingerprint compounds, which may be used to identify the contributions between wood and straw burnings in source apportionment researches.     

滨海新区大气颗粒物中半挥发性有机物污染特征研究

本文通过在天津市滨海新区局部区域汉沽和大港采集TSP和PM10样品,研究了不同颗粒物中半挥发性有机物的不同期别污染和分布特征,结果表明:半挥发性的污染水平存在明显的季节性特征,采暖期半挥发性有机物和可吸入颗粒物中苯并[a]芘浓度均远远高于非采暖期.     

CEMS比对监测结果反映的若干问题探讨

文章以固定污染源比对监测的结果作为参考依据,针对其反映的低浓度颗粒物采样测量、比对监测考核指标的不完善以及火电厂湿法脱硫装置未安装GGH时颗粒物浓度的测定等方面存在相关问题进行了归纳和探讨。     

“十二五”我国大气颗粒物污染防治对策

颗粒物是影响我国环境空气质量的首要污染物。本文深入分析了当前我国大气颗粒物的污染现状和排放控制现状,总结分析污染分布特征,评估重点行业和主要领域大气颗粒物污染控制情况及存在的不足。以此为基础,从管理体系、控制手段和科学研究等方面,提出"十二五"期间大气颗粒物污染防治的对策、措施和建议。     

Effects of continuously regenerating diesel particulate filters on regulated emissions and number-size distribution of particles emitted from a diesel engine

The effects of continuously regenerating diesel particulate filter (CRDPF) systems on regulated gaseous emissions, and number-size distribution and mass of particles emanated from a diesel engine have been investigated in this study. Two CRDPF units (CRDPF-1 and CRDPF-2) with di erent specifications were separately retrofitted to the engine running with European steady-state cycle (ESC). An electrical low pressure impactor (ELPI) was used for particle number-size distribution measurement and mass estimation. The conversion/reduction rate (RCR) of hydrocarbons (HC) and carbon monoxide (CO) across CRDPF-1 was 83% and 96.3%, respectively. Similarly, the RCR of HC and CO and across CRDPF-2 was 91.8% and 99.1%, respectively. The number concentration of particles and their concentration peaks; nuclei mode, accumulation mode and total particles; and particle mass were highly reduced with the CRDPF units. The nuclei mode particles at downstream of CRDPF-1 and CRDPF-2 decreased by 99.9% to 100% and 97.8% to 99.8% respectively; and the particle mass reduced by 73% to 92.2% and 35.3% to 72.4%, respectively, depending on the engine conditions. In addition, nuclei mode particles increased with the increasing of engine speed due to the heterogeneous nucleation initiated by the higher exhaust temperature, while accumulation mode particles were higher at higher loads due to the decrease in the air-to-fuel ratio (A/F) at higher loads.     

四川盆地PM2.5浓度时空变化特征遥感监测与影响因子分析

四川盆地因其独特的地形地貌、静风和高湿等气象条件,导致盆地内部大气污染物扩散难度大,随着城市化与工业化进程加快,区内PM_2.5污染日益加重,四川盆地已成为国家大气污染防治的重点地区之一.基于PM_2.5浓度遥感反演产品,采用空间自相关分析与灰色关联分析方法,研究了四川盆地PM_2.5浓度的时空分布特征及其影响因素.结果表明,四川盆地PM_2.5浓度具有显著的空间聚集性,高-高聚集类型分布集中,低-低聚集类型分布较为分散;针叶林对PM_2.5的吸收抑制作用明显高于灌丛和草地等其他植被类型.研究认为,影响四川盆地PM_2.5浓度的主要气象因子是风速和气温,人口密度与经济规模则是影响四川盆地PM_2.5浓度的主要人类活动因子,产业结构及其规模变化对四川盆地PM_2.5浓度也产生一定影响.     

北京雾霾天大气颗粒物中微生物气溶胶的浓度及粒谱特征

于2013年1月8日~2013年2月4日雾霾频繁暴发期间,使用定量空气微生物采样器和气溶胶粒谱测试仪测试并比较了雾霾天和之后的清朗天气下细菌、真菌气溶胶浓度变化、粒谱分布及不同粒径大小颗粒物的数量浓度差异和粒谱分布特征.结果表明,采样周期内真菌气溶胶小于5μm的粒子(可吸入肺粒子)所占百分比显著高于细菌气溶胶小于5μm的粒子百分比.雾霾过后的晴朗天气下细菌、真菌气溶胶浓度高于雾霾天气时的浓度,而颗粒物浓度则相反.无论雾霾天或晴朗天微生物气溶胶的粒谱分布无显著差别,空气中的颗粒物以PM1.0占绝大多数.